Patent GB-647542-A (GB)
Title: Process for the manufacture of 2-methyl-4-phenylbenzthiazole, methine dyes and sensitized photographic emulsions
IPC: C07D277/64
Filed: 1947-11-13
Abstract: 2-Methyl-4-phenylbenzthiazole is prepared by oxidizing o-thioacetamidodiphenyl, and specifically by treating an aqueous sodium hydroxide solution of the latter compound with aqueous potassium ferricyanide.  Quaternary salts are prepared by heating with an alkyl ester, e.g. methyl, ethyl, n-propyl, or n-butyl p-toluenesulphonate, benzenesulphonate, or iodide, isobutyl or benzyl iodide, n-butyl chloride, n-propyl, b -ethoxyethyl, b -hydroxyethyl, carboxymethyl, carbethoxymethyl, or allyl bromide, or dimethyl or diethyl sulphate.  o-Thioacetamidodiphenyl is prepared by heating a toluene solution of o-acetamidodiphenyl with phosphorus pentasulphide.ALSO:Dyes of the general formula <FORM:0647542/IV (c)/1> wherein d is 1 to 4, n is 1 or 2, L is a substituted or unsubstituted methine group, R and R1 are alkyl, X is an anion, and Z represents the residue of a 5- or 6-membered ring, which may have fused-on benzene rings, (e.g. thiazole or 4-methyl-, 4-phenyl-, or 4 : 5-diphenyl-thiazole; benzthiazole or 5-, 6- or 7-chloro-, 5-dimethylamino-, 4- or 6-methoxy-, 5- or 6-methyl-, or 5-bromo-benzthiazole; a - or b -naphthathiazole; selenazole or 4-methyl- or 4-phenyl-selenazole; benzselenazole or 5-chlorobenzselenazole; benzoxazole or 5-phenyl-, 5-chloro-, or 5-methoxybenzoxazole; or quinoline, or 6-methoxy- or 6-chloro-quinoline) are prepared by the usual methods from quaternary salt of 2-methyl-4-phenylbenzthiazole, e.g. by condensing with a cyclammonium quaternary salt of the general formula <FORM:0647542/IV (c)/2> wherein X is Cl, Br, I, a thioether group, or a group of the formula R2R3N-(L=L)d-1, or of the formula R4S-L=L, wherein R2 is aryl, R3 is H, alkyl, or aryl, and R4 alkyl.  Monomethine cyanine dyes are prepared using cyclammonium quaternary salts of the above general formula such that X1 is Cl, Br, I, or a thioether group.  3 - Ethyl - 31 - methyl - 4 - phenylthiacyanine bromide is prepared by refluxing together 2-methyl-4-phenylbenzthiazole diethyl sulphate and 2-methylmercaptobenzthiazole dimethyl sulphate in alcohol containing triethylamine.  11 : 3 - Diethyl - 61 - methoxy - 4 - phenylthia-21-cyanine bromide and 31-ethyl-3-methyl-41-phenyloxathiacyanine bromide are similarly prepared.  Trimethine cyanine dyes are prepared using cyclammonium quaternary salts of the above general formula such that X1 is R2R3N-CH= CH or R4S-L = L, or, in the case of symmetrical dyes, by condensing a quaternary salt of 2-methyl-4-phenylbenzthiazole with an orthocarboxylic ester (e.g. triethyl, tri-n-propyl, and tri-n-butyl orthoformate; triethyl orthoacetate, orthopropionate, orthophenylacetate, and orthobenzoate; trimethyl ortho-n-valerate and ortho-p-toluate; and methyldiethyl ortho-n-caproate and ortho-iso-caproate). 11-Butyl-3-ethyl-4-phenylthia-41-carbocyanine iodide is prepared by refluxing together 2-methyl-4-phenylbenzthiazole ethyl-p-toluenesulphonate and 4-b -acetanilidovinylquinoline-n-butiodide in pyridine.  3 : 31 - Diethyl - 41 - phenyloxathiacarbocyanine iodide is similarly prepared. 9-Ethyl-3 : 31 - dimethyl - 4 :1 4 - diphenylthiacarbocyanine iodide is prepared by refluxing together 2 - methyl - 4 - phenylbenzthiazole methyl - p - toluenesulphonate and ethyl orthopropionate in pyridine. 3 : 31-Diethyl-4 : 41-diphenylthiacarbocyanine bromide and 3 : 31-diethyl-9-methyl-4 : 41 - diphenylthiacarbocyanine iodide are similarly prepared.  Dyes may also be prepared from intermediates such as 2-(2-methylmercapto - 1 - butenyl) - benzthiazole methyl-p - toluenesulphonate, 2 - (1 - methyl - 2 - methylmercapto - 1 - butenyl) - benzthiazole methyl - p - toluenesulphonate, 2 - (methylmercaptopropenyl) - 3 : 4 - trimethylenebenzthiazolium-p - toluenesulphonate, 5 - chloro - 2 - (2 - methylmercapto - 1 - butenyl) - benzselenazole methyl-p - toluenesulphonate, 2 - (2 - methylmercaptostyryl)-b -naphthathiazole ethiodide, 5-chloro-2 - (b - cyclopropyl : b  - methylmercaptovinyl)-benzthiazole methyl-p-toluenesulphonate, 2-(b -cyclobutyl : b  - methylmercaptovinyl) - benzthiazole methyl-p-toluenesulphonate, and 2-(b -cyclohexyl : b  - methylmercaptovinyl) - benzthiazole methyl-p-toluenesulphonate.  Pentamethine cyanine dyes are prepared using cyclammonium quaternary salts of the above general formula such that X1 is a R5R6N-CH = CH-CH = CH group (R5 being H, alkyl, or acyl, and R6 being aryl), or, in the case of symmetrical dyes, by condensing a quaternary salt of 2-methyl-4-phenylbenzthiazole with a b -arylaminoacrolein anil salt.  11 : 3 - Diethyl - 4 - phenylthia - 41 - dicarbocyanine perchlorate is prepared by refluxing together 2-methyl-4-phenylbenzthiazole ethyl-p-toluenesulphonate and 4-(4-acetanilido-1 : 3-butadienyl)-quinoline ethiodide in alcohol containing triethylamine, and treating a hot methyl alcohol solution of the dye with hot aqueous sodium perchlorate.  3 : 31 - Diethyl - 4 : 41 - diphenylthiadicarbocyanine iodide is prepared by refluxing together 2-methyl-4-phenylbenzthiazole ethyl-p-toluenesulphonate and b -anilinoacrolein anil hydrochloride in ethyl alcohol containing triethylamine, and treating a hot methyl alcohol solution of the dye with hot aqueous potassium iodide.  Heptamethine cyanine dyes are prepared using cyclammonium quaternary salts of the above general formula such that X1 is a R7R8-L = L-L = L-L = L group, R7 being H, alkyl or acyl and R8 being aryl, or, in the case of symmetrical dyes, by condensing a quaternary salt of 2-methyl-4-phenylbenzthiazole with a glutaconic aldehyde dianilide salt.  3 : 31-Diethyl - 4 : 41 - diphenylthiatricarbocyanine bromide is prepared by reacting together 2-methyl-4-phenylbenzthiazole ethyl-p-toluenesulphonate and glutaconic aldehyde dianilide hydrochloride in ethyl alcohol containing piperidine, and treating a hot methyl alcohol solution of the dye with hot aqueous potassium bromide.  Merocyanine dyes of the general formula <FORM:0647542/IV (c)/3> wherein m is 1, are prepared by condensing a quaternary salt of 2-methyl-4-phenylbenzthiazole with an arylaminomethylene compound of general formula <FORM:0647542/IV (c)/4> wherein R10 is H or acyl and R11 is aryl, or by condensing the quaternary salt with an orthocarboxylic ester and p  a compound of the general formula <FORM:0647542/IV (c)/5> 3 - Ethyl - 5 - [(3 - ethyl - 4 - phenyl - 2(3) - benzthiazolylidene) - ethylidene] - rhodanine is prepared by refluxing together 2-methyl-4-phenylbenzthiazole ethyl-p-toluenesulphonate and 5-acetanilidomethylene - 3 - ethylrhodanine in alcohol containing triethylamine. 3-Phenyl-5-[(3- ethyl - 4 - phenyl - 2(3) - benzthiazolylidene) - ethylidene]-rhodanine, and the corresponding 3-methyl-, 3-b -hydroxyethyl-, 3-b -naphthyl-, and 3-lauryldyes, 3-ethyl-5-[(3-ethyl-4-phenyl-2(3)-benzthiazolylidene) - ethylidene] - 2 - thio - 2 : 4 - (3 : 5) - oxazoledione, 3 - ethyl - 5 - [(3 - ethyl - 4 - phenyl - 2(3) - benzthiazolylidene) - ethylidene] - 1 - phenyl - 2 - thiohydantoin, 1 - phenyl - 3 - methyl - 4 - [(3 - ethyl - 4 - phenyl - 2(3) - benzthiazolylidene) - ethylidene] - 5 - pyrazolone, 1 - benzthiazolyl - 3 - methyl - 4 - [(3 - ethyl - 4 - phenyl - 2(3) - benzthiazolylidene) - ethylidene] - 5 - pyrazolone, and 2-diphenylamino-5-[(3-ethyl-4-phenyl-2(3) - benzthiazolylidene) - ethylidene] - 4(5) - thiazolone are similarly prepared. 3-Ethyl-5-[(3-ethyl - 4 - phenyl - 2(3) - benzthiazolylidene) - isopropylidene] - 2 - thio - 2 : 4 - (3 : 5) - oxazoledione is prepared by refluxing together 2 - methyl - 4 - phenylbenzthiazole ethyl - p - toluenesulphonate, 3 - ethyl - 2 - thio - 2 : 4 - (3 : 5)-oxazoledione, and ethyl orthoacetate in alcohol containing triethylamine.  1 : 3-Diethyl-5 - [(3 - methyl - 4 - phenyl - 2(3) - benzthiazolylidene)-ethylidene]-2-thiobarbituric acid, 3-ethyl-5-[(3 - methyl - 4 - phenyl - 2(3) - benzthiazolylidene)-isopropylidene]-rhodanine and the corresponding 3-phenyl- and 3-unsubstituted dyes, and 3-ethyl-5 - [(3 - methyl - 4 - phenyl - 2(3) - benzthiazolylidene) - isopropylidene] - 1 - phenyl - 2 - thiohydantoin and the corresponding 3-phenyldye are similarly prepared.  Merocyanine dyes of the above general formula, wherein m is 2, are prepared by reacting the corresponding simple merocyanine dye with an alkyl ester and then condensing with a 5- or 6-membered heterocyclic ketomethylene compound. 3-Ethyl-5-[(3-methyl-4-phenyl - 2(3) - benzthiazolylidene) - ethylidene] - 2-(5 - ethyl - 4 - oxo - 2 - thiono - 5 - thiazolidylidene)-4-thiazolidone is prepared by heating 3 - ethyl - 5 - [(3 - methyl - 4 - phenyl - 2(3) - benzthiazolylidene) - ethylidene] - rhodanine with methyl-p-toluenesulphonate, and refluxing the product with 3-ethylrhodanine in alcohol containing triethylamine. 2-(3-Carbethoxymethyl-4 - oxo - 2 - thiono - 5 - thiazolidylidene) - 3 - ethyl-5 - [(3 - ethyl - 4 - phenyl - 2(3) - benzthiazolylidene) - ethylidene] - 4 - thiazolidone is similarly prepared.  Specifications 533,238 and 585,666 are referred to.